German Utility Model No. 6 902 052 discloses a watering device for piglings comprising a reservoir or supply tank which has a filling or inlet opening provided at the upper end of said tank and being adapted to be hermetically closed and an outlet opening at the lower end of said tank, said device further comprising a collecting vessel surrounding said outlet opening. The liquid contained in said supply tank can only flow therefrom and into said collecting vessel so long as said outlet opening is not covered by the liquid which has flowed out. Hence the liquid keeps flowing in an amount proportional to the amount of liquid drunk by the piglings. In order to maintain the liquid contained in said collecting vessel or watering trough in a warm condition, a heating means consisting of a closed container filled with hot water is provided beneath said collecting vessel. This heating vessel carries a connected side piece into which an immersion heater can be inserted.
This prior device has a drawback consisting in that before said liquid warms up sufficiently, it must remain in said collecting vessel for rather a long time. Consequently whenever the piglings are thirsty and drink a lot, cold liquid (be it water or milk) will follow so that the piglings may become cold, whereas if the piglings drink the liquid at a later time, then there is danger that the liquid will be spilled, soiled or polluted before it warms up sufficiently.
Furthermore, for achieving a good thermal transfer it is necessary that both the hot water vessel and the watering trough should be made of metal. However, metals corrode very quickly in the wet atmosphere of a pigsty.
What would be more advantageous as regards the transfer of heat would be a heating means projecting directly into said supply tank; such a measure meets, however, with difficulties as regards cleaning and sealing, particularly in the case of liquid tanks operating at below atmospheric pressure and adapted to be closed in a pressure-tight manner.
One object of the invention is to provide a watering and nursing device permitting a problemless heating-up of the liquid in the supply tank by simple means.